Walter s



n the cylinder.

UNITED STATES PATENT OFFICE.

WALTER s. sI-IIPE, or TORONTO, CANADA.

CYLINDRICAL BOILER.

SPECIFICATION forming part of Letters Patent No. 453,946, dated June 9, 1891. Appunti and october 23,1890. 'seria Naseem. on model.)

To all 'whom it may concern.'

l Be it known that I, WALTER SCOTT Stura, of the city of Toronto, in the county of York, in the Province of Ontario, Canada, have invented a certain new and useful Improvement in Cylindrical Boilers, of which the fol-4 lowing is a specification.

The object of the invention is to produce a cylindrical boiler which shall have a smooth exteriorsurface capable of being polished;

and it consists in the construction, arrangement, and combinations of parts hereinafter more particularly-described, and then definitely claimed.

Figure 1 is a sectional elevation of my'improved boiler. Fig. 2 is an enlarged crosssection showing a plan of the longitudinal joint. Fig. 3 is an4 enlargedcross-section of the strip used in forming the longitudinal joint.

Referringnow to the details of construction, A represents the metal sheet forming The edges a. of the longitudinal joint of the cylinder (see Fig. 2) are ben inwardly,- as indicated, to t the recess made in the strip B, as shown in Fig. 3. This strip, as it will be seen on reference tothis iigure, has a rib C, which projects between the edges a, and is riveted or compressed down,-

as shown in Fig. 2,' so as to overlap the edges a and till the depression formed by the bending of the edges a, and in vthis way make a practically invisible joint, which will at the same time be very strong.

.It will be observed that bythe construction describeda perfectly-smooth longitudinal jointis formed iiush with the exterior of the boiler, which would allow of the joint being finished in such a manner as to be quite invisible, especially when the boiler' is polished and then galvanized.

I am aware of the United States Patent No. l57,492,granted for a method of seemingA curved edges of the sheet metal the strip is weakened at this point by the bend, and thus the joint will readily open under great pressure. In rhy construction, on the contrary, the sheet meta-lis bent inward, or toward the center of the boiler, and the bent edges are set in grooves formed in the heaviest part of the strip, forming a channel in which the solid rib is swaged or spread laterally under. a powerful pressure, which not only makes the out-side of the joint substantially or quite flush with thc sheet, but compresses the m'etal in much less space than when in its original form, and has been found by actual experiment to be capable of bearing great strain. This is a great advantage, for these boilers have to bear an immense pressure in some situations; and a me'rebending O.' the flange over the curved edge isnot'suflicient to stand the strain even it the flanges were not weakcned by said bending, as must undoubtedly be the case. Besides this I have afurther advantage in setting on the head, which could not be put on Water-tight in a way that would outside or projecting rib.

What I claim as my invention is- 1. A joint for sheet-metal vessels or other purposes, consisting of the edges of the sheet lnetal which are to be united and of a uniting strip of solid metal, the edges of the sheet metal being bent inward and the strip having grooves to receive them and being provided with a rib riveted or forced into the space bei tween the said vedges and composed of suicient metal to substantially fill the said space, asset forth.

2. A shectanetal plate bent in the form of Y a cylinder, having its longitudinal edges bent inwardly on a compoundangle, in combina` tion with a metal strip 'having ya solid rib withl grooves on each side to receive the inwardly-set edges o t the plate, said rib being tiattened out andiilling the space between the angles of the sheet-metal plate, leaving the outside of the 'cylinder substantially smooth, substantiallyas and for. the purpose set forth.

Toronto, September 23, 1890.

WAI/ER SIIIPE. In presence of CHARLES C. BALDWIN, A. DAWSON.

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